After administering fluids for a hypovolemic patient, which change would be expected?

After administering fluids for a hypovolemic patient, which change would be expected?

• A. Decrease PCWP and CO
• B. No change in PCWP or CO
• C. Increase PCWP and CO
• D. Increase SVR with no change in CO

Answer: (C)

Fluids given to a hypovolemic patient raise venous return to the heart, increasing preload. PCWP (pulmonary capillary wedge pressure) is a surrogate for left-sided preload, so it rises when you volume-load. With more preload, the heart can eject more blood per beat due to the Frank-Starling mechanism, so cardiac output increases as well. That’s why the expected change is an increase in both PCWP and CO. The other patterns don’t fit. A decrease in PCWP and CO would suggest preload fell or the heart isn’t responding to the volume, which isn’t the typical response to a fluid bolus in a preload-responsive patient. No change implies the bolus had no effect, which is unlikely if preload is low and the heart is operating on the ascending limb of the Frank-Starling curve. An increase in systemic vascular resistance with no change in CO doesn’t align with the expected improvement in preload and cardiac performance after volume expansion, where CO would usually rise.

Fluids given to a hypovolemic patient raise venous return to the heart, increasing preload. PCWP (pulmonary capillary wedge pressure) is a surrogate for left-sided preload, so it rises when you volume-load. With more preload, the heart can eject more blood per beat due to the Frank-Starling mechanism, so cardiac output increases as well. That’s why the expected change is an increase in both PCWP and CO.

The other patterns don’t fit. A decrease in PCWP and CO would suggest preload fell or the heart isn’t responding to the volume, which isn’t the typical response to a fluid bolus in a preload-responsive patient. No change implies the bolus had no effect, which is unlikely if preload is low and the heart is operating on the ascending limb of the Frank-Starling curve. An increase in systemic vascular resistance with no change in CO doesn’t align with the expected improvement in preload and cardiac performance after volume expansion, where CO would usually rise.